JPS6216589A - Laser device for separating isotope - Google Patents

Abstract

PURPOSE:To hold the wavelength of laser beams stable by detecting a deviation between the wavelength of laser beams used for separating an isotope and a specific wavelength required for separating the isotope with high precision by a discharge tube having optical absorption characteristics. CONSTITUTION:A pump laser 2 is given pulses having required frequency from a pulse generator 1 and pulse-oscillated. Laser beams R2 are outputted from the pump laser 2, and projected to a wavelength selective laser 3. The wavelength selective laser 3 selectively outputs laser beams R3 having a specific wavelength needed for separating an isotope from laser beams R2 projected to an isotope separator 4. The same isotope as the isotope to be separated is attached to an electrode, and the wavelength of laser beams R3 is detected at all times by a hollow cathode lamp 8 having optical absorption characteristics. Accordingly, the wavelength can be detected with high accuracy, and the wavelength of laser beams R3 can be held stable to the specific wavelength.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a laser device for isotope separation that outputs a laser beam of a specific wavelength necessary for isotope separation, and particularly relates to a laser device for isotope separation that outputs a laser beam of a specific wavelength necessary for isotope separation. This invention relates to a laser device for isotope separation with an improved wavelength detector.

[Technical background of the invention and its problems]

In general, laser isotope separation is a method that utilizes isotope shift effects to selectively excite and ionize specific isotopes using a laser beam of an unspecified wavelength.

In general, atoms absorb light of a specific wavelength to change from the ground state to an excited state, and then in the excited state absorb light of another specific wavelength to reach a higher excited state, or lose electrons and become ionized. Causes ionization phenomenon. During this photoionization, atoms! The specific wavelength of light that is easy to collect is different even if the elements are the same.
If the numbers are different, they may be slightly different. This is called an isotope shift.

In this way, the isotope shift of an element is extremely small, so in order to perform isotope separation efficiently, it is necessary to maintain the laser beam used for this purpose at a specific wavelength with high precision and stability. be. Of course, the accuracy of the wavelength of the laser beam used for isotope separation is, for example, uranium-235
In this case, it is required that the deviation for a specific wavelength be within 17106.

Therefore, in conventional Raded isotope separation devices, the laser beam was adjusted to a specific wavelength using an ultra-high precision wavelength meter calibrated with the absorption spectrum of a specific element, such as iodine. However, it is not always easy to adjust the laser beam to a specific wavelength required for isotope separation. In addition, maintaining the laser beam at a specific wavelength during isotope separation is not as easy as adjusting it because it requires an ultra-high precision wavelength meter to be in constant operation.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a laser device for isotope separation that can maintain a laser beam at a specific wavelength with high precision and stability.

[Summary of the invention]

The present invention was made by focusing on the light absorption effect of the isotope to be separated, and by using a discharge tube with this light absorption characteristic, the wavelength of the laser beam used for isotope separation and the isotope separation can be adjusted. The feature is that the deviation from the required specific wavelength is detected using high viscosity, and the wavelength of the laser beam is stably maintained at the specific wavelength.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, in which a pulse generator 1 supplies pulses of a desired frequency to a pump laser 2 to cause pulse oscillation. Laser light R2 is output from the pump laser 2 and is incident on the wavelength selective laser 3. The wavelength selective laser 3 selectively outputs a laser beam R3 having a specific wavelength necessary for isotope separation from the incident laser light R2 to the isotope separation device 4.

The wavelength-selective laser 3 is configured as shown in FIG.
c, the beam is made incident on the etalon 3d and the diffraction grating 3e. The airtight chamber 3b is equipped with a plurality of pressure control valves 3f, for example two pressure control valves, and the opening degree of the internal pressure control valve 3f is controlled by a wavelength control signal S5 from a wavelength controller 5. By controlling the opening degree of the internal pressure control valve 3f, the pressure within the airtight chamber 3b is changed, and the wavelength of the laser beam R3 output from the output mirror 3g is appropriately controlled. Further, the wavelength of the laser beam R3 can be controlled by slightly adjusting the angle of the diffraction grating 3e and etalon 3d, which are wavelength selection elements, with respect to the laser optical axis in the direction of the arrow in the figure. The laser light from this diffraction grating 3e and etalon 3d passes through the wavelength-selective laser excitation m13a again, and is transmitted through the semi-transmissive mirror 6 as a laser beam R3 from the output mirror 3g.
On the other hand, a part of the laser beam R3 reflected by the semi-transmissive mirror 6 is used as a monitor beam R6 as shown in FIG. The hollow cathode lamp 8 is separated through the reflective mirror 7.
is incident on the This cathode lamp 8 is a discharge tube that discharges at a high DC voltage, and one of its electrodes, for example 8a, contains an isotope element U that is the same as the isotope to be separated in the isotope separation device 4. It is attached to produce an opto-galvanic effect. That is, when the wavelength of the monitoring beam R6 incident on the hollow cathode lamp 8 coincides with the resonance absorption line of the isotope element U during discharge, the impedance of the discharge plasma decreases rapidly. Therefore, this impedance change can be detected by the capacitor C as a discharge voltage change. Thereby, the borrow cathode lamp 8 detects the deviation of the wavelength of the monitoring beam R6 from the specific wavelength required for isotope separation. This deviation is input to the lock-in amplifier 9 as an opto-galvano signal S8, which is an electric signal, and here the pulse is converted into a pulse of output x1 and input to the wave tower controller 5. The wavelength controller 5 applies a wavelength control signal S5 corresponding to the opto-galvano signal S8 to both pressure control valves 3f (see FIG. 2) of the wavelength selective laser 3 to control their opening degrees. Thereby, the wavelength of the laser beam R3 output from the output mirror 30 is controlled to a specific wavelength necessary for isotope separation.

Therefore, according to this embodiment, the same isotope element as the isotope to be subjected to isotope separation is attached to the electrode, and the wavelength of the laser beam R3 is constantly controlled by the hollow cathode lamp 8 that controls the light absorption characteristics. Therefore, the wavelength can be detected with high precision, and the wavelength of the laser beam R3 can be stably maintained at a specific wavelength. the result,
When performing isotopic separation of rare components among multiple isotopes, the wavelength of the laser beam used for isotope separation can be adjusted with high precision by concentrating the rare components and attaching them to the hollow cathode lamp electrode. can be detected. For example, when isotopically separating uranium 235 from natural uranium, highly enriched uranium 235 may be attached to the electrode 8a of the hollow cathode lamp 8.

〔Effect of the invention〕

As explained above, the present invention includes a wavelength-selective laser that receives laser light from a pump laser, oscillates, and selectively outputs a C-11 beam of a specific wavelength necessary for isotope separation, and a wavelength-selective laser that performs isotope separation. a wavelength detector that detects a deviation from the specific wavelength by making a part of the radar beam incident on a discharge tube whose electrode is attached with the same isotopic element as the intended isotope;
A wavelength controller is provided which applies a wavelength control signal to the wavelength selective laser in accordance with the deviation output from the wavelength detector to control the wavelength of the radar beam to the specific wavelength.

Therefore, according to the present invention, since the wavelength of the laser beam used for isotope separation is constantly detected by a wavelength detector having light absorption characteristics, the detection accuracy can be improved.

In addition, since the wavelength of the laser beam is controlled to the specific wavelength required for isotope separation based on the detection output from a high-precision wavelength detector, the wavelength of the laser beam can be stably maintained at a specific wavelength. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, and FIG. 2 is a block diagram mainly showing the configuration of the wavelength selective laser shown in FIG. 1. 1...Pulse generator, 2...Pump laser, 3...
・Wavelength selective laser, 4... Isotope separation device, 5...
- Wavelength controller, 8...Hollow cathode lamp (wavelength detector).

Claims (1)

[Claims] 1. Isotope separation is attempted using a wavelength selective laser that receives laser light from a pump laser and oscillates to selectively output a laser beam of a specific wavelength necessary for isotope separation. A wavelength detector that detects the deviation from the specific wavelength by making a part of the laser beam incident on the discharge tube whose electrode is attached with the same isotopic element as the isotope; and a wavelength detector that detects the deviation from the specific wavelength; a wavelength controller that applies a wavelength control signal to the wavelength selective laser to control the wavelength of the laser beam to the specific wavelength. 2. The laser device for isotope separation according to claim 1, wherein the discharge tube is a hollow cathode lamp.